I hope I do not get killed for this, but one of the best Internet sites that I have found that has vegetarian recipes is run by a Turkish woman who lives in the USA. http://almostturkish.blogspot.com/.
This blog obviously relies on olive oil but I think that we allowed that on Saturdays and Sundays during the second through sixth weeks.
I'd also recommend searching for Indian recipes (as long as you like that sort of thing) - they have loads of vegetarian food that is or can easily be adapted to be fast friendly. I've also recently found that there's a fair bit of Carribean food that's lenten, and as I have a really good greengrocer locally, full of both South Asian and Carribean produce, that's perfect.
Really my only actual fasting cookbook is one I picked up in Romania, but that's in Romanian and as far as I know has not been translated into English, otherwise I'd recommend that. Most of the time, though, I'd say that I cook my fasting food from standard cookbooks, just picking recipes carefully and adapting them where necessary. It's not so hard to do.